2.3 ORDER OF PRECEDENCE ................................................................................................83.0REQUIREMENTS ........................................................................................................83.1 GENERAL REQUIREMENTS .............................................................................................8

This specification establishes the procurement, quality assurance, performance and qualification requirements for flex cable used on the Tracker (TKR) subsystem. Verification of flex cable is accomplished through the use of product assurance provisions defined herein. Detail requirements, specific characteristics, and dimensions of the flex cable, are specified in the flex cable drawing. This specification does not address flex cable parts and connector assembly and installation of the cable to the tracker.

2.0 APPLICABLE DOCUMENTS

2.1 Government/Military Specifications and Standards

The following specifications and standards form a part of this specification to the extent specified herein. Unless otherwise specified, the applicable issues of these documents shall be those listed in the issue of the Department of Defense Index of Specifications and Standards (DoDISS), and the applicable supplement thereto, in effect on the date of the procurement.

The following documents forma a part of this specification to the extent specified herein. The applicable issues of these documents shall be that or those in effect by the responsible industry association or society on the date of the procurement documents.

IPC-2221Generic Standard on Printed Board Design

IPC-2223Sectional Design Standard for Flexible Printed

Boards

IPC-6013Qualification & Performance Specification for Flexible

Printed Boards

IPC-A-600Acceptability of Printed Boards

IPC-TM-650IPC Test Methods

LAT-PS-01132 DRAFT Page 8 of 29

2.3 Order of Precedence

In the event of a conflict between the procurement document(s), the text of this document and the references cited herein, the following order of precedence, shall apply:

1) Contract or purchase order.

2) Flex cable drawing

3) This specification

4) Other documents referenced herein

3.0 REQUIREMENTS

3.1 General requirements

Flex cable furnished to this specification shall conform to the requirements of the LAT Tracker Kapton Flex Cable drawing, this specification, and IPC-6013. The detailed requirements contained in this section are determined by examining specific quality conformance test circuitry (test coupons) and sample flexible cable, shall apply to all coupons, sample flexible cable, and delivered flexible cable. Defects or anomalies noted on coupons or sample cables (or both) when performing the inspections defined herein shall be recorded and the proper corrective actions shall be initiated to eliminate the defects or anomalies.

3.1.1 LAT Tracker Kapton Flex Cable Flex cable drawing

Flex cables delivered under this specification shall be of the material, design, and construction specified on the flex cable drawing. If individual design details are not specified on the drawing, then the baseline design parameters shall be as detailed in the design standard IPC-2223.

3.1.2 Conflicting requirements

In the event of conflict between the requirements of this specification and other requirements of the drawing, the precedence in which documents shall govern, in descending order, is as follows:

a. The drawing. Additional acquisition requirements may be provided in the

order or contract. Any deletion of any of the performance requirements or

performance verifications of this specification not approved by the activity, will

result in the flex cable being deemed noncompliant with this specification.

Flex cable shall be of the design as specified on the drawing. If individual design details are not specified on the applicable drawing, then the baseline design parameters to be used for acceptability of finished product requirements shall be as detailed in IPC-2223 that was used to design the flexible cable.

Test coupon design, quantity, placement, and usage shall be in accordance with IPC-2223.

Artwork factoring to compensate for material movement after etch is almost mandatory; thoughtful material choice at the design stage, plus clear definition of the material and quality requirements in drawing notes, is essential to close the control loop. Optional alignment to etched fiduciaries is one of the methods for reducing alignment errors, which reduces the effect of artwork pinning errors and after-etch shrinkage. 3.2.2 Flex Cable Lay-up

Figure 1 shows the lay-up for the four-layer flex cable. The total thickness is 450 ;m

(18 mils) nominal. The minimum thickness can include the adhesive. The following is the justification for each material thickness:

？ All copper are required to be a minimum of 1 oz., Type 3.

？All other dielectrics are a minimum of 0.008” between layer 2 and 3.

？The top and bottom cover layer is a minimum of 0.001”.

？ Solder pads shall be left exposed

LAT-PS-01132 DRAFT Page 10 of 29

LF0210Kapton Covercoat0.00100

Acrylic Adhesive0.00200

Layer 11 oz. Copper + PlatingRolled/Annealed + ED Copper0.00350

Acrylic Adhesive0.00100

LF9111Kapton Basefilm0.00100

Acrylic Adhesive0.00100

Layer 21 oz. CopperRolled/Annealed + ED Copper0.00140

Acrylic Adhesive0.00100

AD1LF0121Kapton Basefilm0.00200

Acrylic Adhesive0.00100

Acrylic Adhesive0.00100

AD2LF0121Kapton Basefilm0.00200

Acrylic Adhesive0.00100

Layer 31 oz. CopperRolled/Annealed + ED Copper0.00140

Acrylic Adhesive0.00100

LF9111Kapton Basefilm0.00100

Acrylic Adhesive0.00100

Layer 41 oz. Copper + PlatingRolled/Annealed + ED Copper0.00350

Acrylic Adhesive0.00200

LF0210Kapton Covercoat0.00100

Total Thickness0.03000

Nominal Dielectric Thickness is .008”

Table 1.Tracker Flex Cable Lay-up

3.2.3 Impedance Specification

The ordering of the layers is shown in figure1. The signal traces are nominally 150 Ohm Differential Impedance. The signals NTREQxxx, NTOKENxxx, NSDATAxx, and TEMPxx shall have 10-mil trace width. The signals NRESETxx, CLKx, NTACKx, and NSCMDx shall have 12-mil traces from J1 to two inches from J2 on the main cable, and 8-mils all the rest of the routing. The xxx represents the signal suffixes. Differential pairs shall be routed together and spaced away from other pairs.

3.2.4 Surface Mount Design Consideration

The following surface mount design guidelines will be followed:

1. Pads should be coverlayered or covercoated to prevent solder escape-apertures

should define the best area for device attachment.

2. Pads should extend well underneath the coverlayer or covercoat to increase

resistance to pad lifting form the attach and rework cycles.

3. Coverlayer of covercoat thickness should be minimal to minimize impact on

solder-cream deposition and device attachment. Because the coverlayer could

prevent the device from settling into contact during reflow, it‟s possible that